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A Theoretical Investigation of Longitudinal Stability of Airplane with Free Controls Including Effect of Friction in Control System

Description: "The relation between the elevator hinge-moment parameters and the control-forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short-period oscillations is shown as a series of boundaries giving the limits of the stable region in terms of the elevator hinge-moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considere… more
Date: December 23, 1943
Creator: Greenberg, Harry & Sternfield, Leonard
Partner: UNT Libraries Government Documents Department
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The Advantages of Uniform Fuel Distribution for Air-Cooled Engines From Considerations of Cooling Requirements and Fuel Economy

Description: "The purpose of this report is to show by analysis of existing data, pending direct experimental determination, the extent to which nonuniform distribution of fuel to cylinders of a multicylinder engine can produce temperature deviation and the benefits to be anticipated from attainment of uniform fuel distribution" (p. 1).
Date: December 1943
Creator: Rubert, K. F.; Corson, Blake W., Jr. & Nielsen, Jack
Partner: UNT Libraries Government Documents Department
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Bearing strengths of bare and alclad XA75S-T and 24S-T81 aluminum alloy sheet

Description: From Introduction: "A report was recently issued covering an investigation of the bearing properties of the wrought aluminum alloys commonly used in aircraft construction (reference 1). Since this work was undertaken, two new materials, XA75S-T and 24S-T81, have been developed to the commercial stage for aircraft use. The objection of this investigation was to determine the bearing yield and ultimate strengths of these new materials in the form of bare and alclad sheet."
Date: December 1943
Creator: Moore, R. L. & Wescoat, C.
Partner: UNT Libraries Government Documents Department
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A comparison at high speed of the aerodynamic merits of models of medium bombers having thickened wing roots and having wings with nacelles

Description: Report presenting testing of models of medium-bomber designs to investigate the relative characteristics of thickened wing roots with propeller-shaft fairings and wings with nacelles. Incremental drag coefficients due to thickened wing roots and due to propeller-shaft fairings through a range of Mach numbers at lift coefficient 0.10. Results regarding force tests, pressure-distribution tests, effect of thickening and filleting, nacelles and propeller-shaft fairings, and a comparison of submerge… more
Date: December 1943
Creator: Draley, Eugene C.
Partner: UNT Libraries Government Documents Department
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Construction of Wire Strain Gages for Engine Application

Description: Report presenting instructions for winding, baking, and mounting a phanolic resin-impregnated, bobbin-type wire strain gage that consists of Advance wire wound around a paper form. A description of some test equipment useful for establishing the merits of the techniques used in gage construction has been included.
Date: December 1943
Creator: Nettles, J. Cary & Tucker, Maurice
Partner: UNT Libraries Government Documents Department
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Correlation of single-cylinder cooling tests of a Pratt and Whitney R-2800-21 engine cylinder with wind-tunnel tests of a Pratt and Whitney R-2800-27 engine

Description: Report presenting an equation in which it is possible to correlate the cooling characteristics of an engine. Results regarding engine cooling, engine performance, and estimated cooling-pressure-drop requirements are provided.
Date: December 1943
Creator: Ellerbrock, Herman H., Jr.
Partner: UNT Libraries Government Documents Department
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The Coupling of Flexural Propeller Vibrations with the Torsional Crankshaft Vibrations

Description: The exact mathematical treatment of the problem is possible by replacing the propeller blade by a homogeneous prismatic rod. Conclusions can them be drawn as to the behavior of an actual propeller, since tests on propeller blades have indicated a qualitative agreement with the homogeneous rod. The natural frequencies are determined and the stressing of the systems under the various vibration modes are discussed.
Date: December 1943
Creator: Meyer, J.
Partner: UNT Libraries Government Documents Department
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Determination of the Mass Moments and Radii of Inertia of the Sections of a Tapered Wing and the Center-of-Gravity Line Along the Wing Span

Description: "For computing the critical flutter velocity of a wing among the data required are the position of the line of centers of gravity of the wing sections along the span and the mass moments and radii of inertia of any section of the wing about the axis passing through the center of gravity of the section. A sufficiently detailed computation of these magnitudes even if the weights of all the wing elements are known, requires a great deal of time expenditure. Thus a rapid competent worker would requ… more
Date: December 1943
Creator: Savelyev, V. V.
Partner: UNT Libraries Government Documents Department
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The Effect of Surface Finish on the Fatigue Performance of Certain Propeller Materials

Description: Report presenting an investigation of the effect of various surface finishes on the endurance of normalized X4130 and 4140 steels and 25S-T aluminum alloy. All mechanically formed surfaces tested were stronger than electropolished surfaces.
Date: December 1943
Creator: Russell, H. W.; Gillett, H. W.; Jackson, L. R. & Foley, G. M.
Partner: UNT Libraries Government Documents Department
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Fatigue Strength and Related Characteristics of Spot-Welded Joints in 24S-T Alclad Sheet

Description: Report presenting an investigation on spot-welded 24S-T Alclad. The report is divided into five parts, including an investigation of tension fatigue measurements, lap-joint samples spot-welded by different companies, fatigue strengths of wire-stitched lap-joint samples, data on similar samples with different spot spacings, and the results of compression fatigue tests for stiffened panels with purposely overheated spot welds.
Date: December 1943
Creator: Russell, H. W.
Partner: UNT Libraries Government Documents Department
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Flight tests of beveled-trailing-edge ailerons with various modifications on a North American XP-51 airplane (AAF No.41-38)

Description: Report presenting flight testing using a North American XP-51 airplane with several arrangements of beveled-trailing-edge ailerons to determine the most satisfactory arrangement. Results regarding the aileron configuration, trimming tabs, and factors affecting symmetry of aileron characteristics are provided.
Date: December 1943
Creator: White, Maurice D. & Hoover, Herbert H.
Partner: UNT Libraries Government Documents Department
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Flight tests of F2A-2 airplane with full-span slotted flaps and trailing-edge and slot-lip ailerons

Description: Report presenting flight tests of a Navy F2A-2 specially equipped with full-scale slotted flaps and two sets of lateral controls: internally balanced, sealed ailerons on the flap trailing edge for use with the flaps up and slot lip ailerons for use with the flaps down. Results regarding aileron characteristics, maximum lift coefficients and stalling characteristics, and longitudinal stability and control are provided.
Date: December 1943
Creator: Wetmore, Joseph W.
Partner: UNT Libraries Government Documents Department
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Flight Tests of Various Tail Modifications on the Brewster XSBA-1 Airplane 2: Measurements of Flying Qualities with Tail Configuration Number Two

Description: Several tail modifications of the Brewster XSBA-1 scout-bomber were investigated and results compared. Modifications consisted of variation of the chord of the elevator and rudder while the total area of the surfaces is kept constant and variations of the total area of the vertical tail surface. Configuration number 2 reduced trim changes by 50 percent and reduced average elevator control force gradient from 30 to 27 pounds/g. Stick travel required to stall in maneuver was 4.6 inches.
Date: December 1943
Creator: Phillips, W. H. & Crane, H. L.
Partner: UNT Libraries Government Documents Department
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Heat Transfer and Hydraulic Flow Resistance for Streams of High Velocity

Description: "Problems of hydraulic flow resistance and heat transfer for streams with velocities comparable with acoustic have present great importance for various fields of technical science. Especially, they have great importance for the field of heat transfer in designing and constructing boilers.of the "Velox" type. In this article a description of experiments and their results as regards definition of the laws of heat transfer in differential form for high velocity air streams inside smooth tubes are … more
Date: December 1943
Creator: Lelchuk, V. L.
Partner: UNT Libraries Government Documents Department
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Investigation of Flow in an Axially Symmetrical Heated Jet of Air

Description: The work done under this contract falls essentially into two parts: the first part was the design and construction of the equipment and the running of preliminary tests on the 3-inch jet, carried out by Mr. Carl Thiele in 1940; the second part consisting in the measurement in the 1-inch jet flow in an axially symmetrical heated jet of air.
Date: December 1943
Creator: Corrsin, Stanley
Partner: UNT Libraries Government Documents Department
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Limitations of lifting-line theory for estimation of aileron hinge-moment characteristics

Description: Report presenting hinge-moment parameters for several typical ailerons, which were calculated from section data with the aspect-ratio correlation as usually determined from lifting-line theory. The calculations showed that the agreement between experimental and calculated results was unsatisfactory.
Date: December 1943
Creator: Swanson, Robert S. & Gillis, Clarence L.
Partner: UNT Libraries Government Documents Department
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Measurements in Flight of the Stability, Lateral Control, and Stalling Characteristics of an Airplane Equipped With Full-Span Zap Flaps and Spoiler-Type Ailerons

Description: Report presenting the stability, lateral-control, and stalling characteristics of an airplane modified to accommodate full-span Zap flaps.The static and dynamic longitudinal and lateral stability was satisfactory, but there were some undesirable lateral-control characteristics, including excessive friction and elasticity.
Date: December 1943
Creator: Spahr, J. Richard & Christophersen, Don R.
Partner: UNT Libraries Government Documents Department
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Methods and Charts for Computing Stability Derivatives of a V-Bottom Planing Surface

Description: Report presenting methods and charts for computing stability derivatives of a longitudinally straight V-bottom planing surface representing the forebody of a seaplane float or a flying-boat hull without chine flare. The charts for computing hydrodynamic derivatives were used in calculating the trim limit of stability for angles of dead rise of 10, 20, and 30 degrees.
Date: December 1943
Creator: Benson, James M. & Freihofner, Anton
Partner: UNT Libraries Government Documents Department
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Operating Temperatures of a Sodium-Cooled Exhaust Valve as Measured by a Thermocouple

Description: "A thermocouple was installed in the crown of a sodium-cooled exhaust valve. The valve was then tested in an air-cooled engine cylinder and valve temperatures under various engine operating conditions were determined. A temperature of 1337 F was observed at a fuel-air ratio of 0.064, a brake mean effective pressure of 179 pounds per square inch, and an engine speed of 2000 rpm" (p. 1).
Date: December 1943
Creator: Sanders, J. C.; Wilsted, H. D. & Mulcahy, B. A.
Partner: UNT Libraries Government Documents Department
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Piston Ring Pressure Distribution

Description: "The discovery and introduction of the internal combustion engine has resulted in a very rapid development in machines utilizing the action of a piston. Design has been limited by the internal components of the engine, which has been subjected to ever increasing thermal and mechanical stresses. Of these internal engine components, the piston and piston rings are of particular importance and the momentary position of engine development is not seldom dependent upon the development of both of the … more
Date: December 1943
Creator: Kuhn, M.
Partner: UNT Libraries Government Documents Department
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Preliminary Aerodynamic and Structural Tests Showing the Effect of Compressive Load on the Fairness of a Low-Drag Wing Specimen With Chordwise Hat-Section Stiffeners

Description: Report presenting an investigation that is part of a research program to obtain structures suitable for low-drag wings. The purpose of this particular investigation was to study the drag characteristics of an NACA 66(215)-(1.25)16 airfoil specimen of two-spar construction with hat-section chordwise stiffeners after a compressive load comparable with the maximum applied flight load of a modern military airplane has been applied and removed. Results regarding the variation of section drag coeffic… more
Date: December 1943
Creator: Davidson, Milton; Houbolt, John C.; Rafel, Normal & Rossman, Carl A.
Partner: UNT Libraries Government Documents Department
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A Preliminary Study of Machine-Countersunk Flush Rivets Subjected to a Combined Static and Alternating Shear Load

Description: Report discusses the results of an investigation to study the effect of the height of a rivet head on the number of cycles required to cause failure of a machine-countersunk flush-riveted joint under a combined static and alternating shear load. A tight joint and a loose joint were tested and the number of cycles to failure and location of fatigue failure were compared.
Date: December 1943
Creator: Crate, Harold
Partner: UNT Libraries Government Documents Department
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Propellers in yaw

Description: Report presenting the propeller forces due to an angular velocity of pitch, which are analyzed and shown to be very small for the pitching velocities that may actually be realized in maneuvers, with the exception of the spin. A dual-rotating propeller in yaw was found to develop up to one-third more side force than a single-rotating propeller.
Date: December 1943
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department
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Proposal for a Propeller Side-Force Factor

Description: Report discusses a proposal for propeller manufacturers to consider the side-force factor with the activity factor as a fundamental parameter for all blade designs and for the side-force factor to be included in all reports of powered models in wind tunnels. The proposal includes a method for calculating the side-force factor and how it can be used in propeller development. It is shown to be a good index of the relative effectiveness per blade of a yawed propeller in developing side force.
Date: December 1943
Creator: Ribner, Herbert S.
Partner: UNT Libraries Government Documents Department
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